TTF–TCNE a charge transfer π–molecular crystal with partial ionic ground state: Optical properties and electron‐molecular vibrations interaction

1996 ◽  
Vol 105 (2) ◽  
pp. 397-407 ◽  
Author(s):  
M. Meneghetti ◽  
C. Pecile
Keyword(s):  
Optical Properties ◽  
Charge Transfer ◽  
Ground State ◽  
Molecular Crystal ◽  
Molecular Vibrations ◽  
A Charge

Fluorescence Quenching of Aminodiphenylamines with Chloromethanes

2002 ◽  
Vol 67 (8) ◽  
pp. 1154-1164 ◽  
Author(s):  
Nachiappan Radha ◽  
Meenakshisundaram Swaminathan
Keyword(s):  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Ground State ◽  
Rate Constants ◽  
Quenching Mechanism ◽  
Quenching Rate ◽  
Charge Transfer Interaction ◽  
Electronically Excited ◽  
A Charge

The fluorescence quenching of 2-aminodiphenylamine (2ADPA), 4-aminodiphenylamine (4ADPA) and 4,4'-diaminodiphenylamine (DADPA) with tetrachloromethane, chloroform and dichloromethane have been studied in hexane, dioxane, acetonitrile and methanol as solvents. The quenching rate constants for the process have also been obtained by measuring the lifetimes of the fluorophores. The quenching was found to be dynamic in all cases. For 2ADPA and 4ADPA, the quenching rate constants of CCl4 and CHCl3 depend on the viscosity, whereas in the case of CH2Cl2, kq depends on polarity. The quenching rate constants for DADPA with CCl4 are viscosity-dependent but the quenching with CHCl3 and CH2Cl2 depends on the polarity of the solvents. From the results, the quenching mechanism is explained by the formation of a non-emissive complex involving a charge-transfer interaction between the electronically excited fluorophores and ground-state chloromethanes.

Spectra of the 1:1 and 3:1 solid complexes of coronene-TCNQ

1977 ◽  
Vol 55 (21) ◽  
pp. 3712-3716 ◽  
Author(s):  
Kim Doan Truong ◽  
André D. Bandrauk
Keyword(s):  
Charge Transfer ◽  
Absorption Spectra ◽  
Electronic Absorption ◽  
Ground State ◽  
Electronic Absorption Spectra ◽  
Charge Transfer Band ◽  
Out Of Plane ◽  
The Individual ◽  
A Charge ◽  
Solid Complexes

Two new solid TCNQ complexes have been isolated, coronene–TCNQ 1:1 and 3:1. The infrared and electronic absorption spectra are presented for the two different stoichiometries. From these spectra we infer that the complexes are covalent in the ground state with a charge transfer band appearing at 730 nm. The out of plane vibrations of the individual molecules are noticeably perturbed upon complexation.

CHAMELEON GROUND STATE AND EXCITED STATES OF EDT-TTF-IM-F4TCNQ RADICAL DYAD IN DIFFERENT ENVIRONMENTS

2012 ◽  
Vol 11 (03) ◽  
pp. 505-525 ◽  
Author(s):  
YUHUA ZHOU ◽  
KAI TAN ◽  
XIN LU
Keyword(s):  
Charge Transfer ◽  
Solid State ◽  
Excited States ◽  
Ground State ◽  
Density Functional ◽  
Solvent Polarity ◽  
Functional Study ◽  
Polar Solvents ◽  
Model Calculations ◽  
A Charge

We have performed a systematic density functional study on the ground-state electronic structure and excited states of a representative D-σ-A dyad, i.e. EDT-TTF-Im-F4TCNQ π-radical, in vacuo and in different conventional solvents (toluene, THF, DMF and DMSO) by using some popular hybrid density functionals (B3LYP, M05, M05-2X, PBE0 and BMK). It has been shown that the M05 and B3LYP functionals perform the best in predicting the intramolecular charge-transfer (ICT) pertaining to both the ground state and excited states of the dyad. The amphoteric dyad is liable to solvent-promoted ICT from its EDT-TTF-Im donor (D) to F4TCNQ acceptor (A), adopting a charge-unseparated ground state D-A• in vacuo, a partially zwitterionic ground state [D-A]• in nonpolar toluene solvent, and a fully zwitterionic ground state D•+-A- in such polar solvents as THF, DMF and DMSO. Owing to its solvent-dependent chameleon ground state, excited states of the dyad in solvents also exhibit remarkable dependence on solvent polarity, as revealed by TDDFT calculations. Furthermore, cluster model calculations revealed that intermolecular charge-transfer readily occurs between the dyads, accounting for the observed zwitterionic charge state in solid state and solid-state semiconductivity.

Steady-state and transient-state optical properties of a charge-transfer composite material MO-PPV/SWNTs

2008 ◽  
Vol 451 (1-3) ◽  
pp. 116-120 ◽  
Author(s):  
Saisai Chu ◽  
Wenhui Yi ◽  
Shufeng Wang ◽  
Fengming Li ◽  
Wenke Feng ◽  
...  
Keyword(s):  
Composite Material ◽  
Optical Properties ◽  
Charge Transfer ◽  
Steady State ◽  
Transient State ◽  
A Charge

Charge Transfer Initializes Photoexcited YOYO-1 Intramolecular Rotation and Fluorescent Quenching

2017 ◽  
Author(s):  
Jixin Chen ◽  
Lei Wang ◽  
Joseph R. Pyle
Keyword(s):  
Charge Transfer ◽  
Ground State ◽  
Transient Absorption ◽  
Thermal Relaxation ◽  
Excited Electron ◽  
Transient Absorption Spectroscopy ◽  
Cyanine Dye ◽  
Femtosecond Transient Absorption ◽  
A Charge ◽  
Intramolecular Rotation

YOYO-1 is a commonly used cyanine dye for DNA staining that is fluorescently bright in DNA but very dim in water. The major assumption of its excited electron decay pathway is thermal relaxation via the rotation at a bridging methine that connects the two moieties of the molecule, i.e. photo-isomerization. In this report, we use femtosecond transient absorption spectroscopy to directly measure the excited electron decay, the hole refill, and the hot ground state rise and decay. The data suggest that the first step of the photo-isomerization involves a charge transfer to quench the holes and vibrational activation of the molecules to a hot ground state.

Probing photoinduced phase transition in a charge-transfer molecular crystal by 100 picosecond X-ray diffraction

2004 ◽  
Vol 299 (2-3) ◽  
pp. 163-170 ◽  
Author(s):  
Laurent Guérin ◽  
Eric Collet ◽  
Marie-Hélène Lemée-Cailleau ◽  
Marylise Buron-Le Cointe ◽  
Hervé Cailleau ◽  
...  
Keyword(s):  
Phase Transition ◽  
Charge Transfer ◽  
Molecular Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Charge

Ground state optical properties of charge transfer crystals close to the neutral‐ionic interface: Tetrathiafulvalene‐2,5‐dichloro‐p‐benzoquinone

1993 ◽  
Vol 98 (10) ◽  
pp. 7692-7698 ◽  
Author(s):  
Alberto Girlando ◽  
Anna Painelli ◽  
Cesare Pecile ◽  
Gianluca Calestani ◽  
Corrado Rizzoli ◽  
...  
Keyword(s):  
Optical Properties ◽  
Charge Transfer ◽  
Ground State
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